1. Field of Invention
This invention relates to the utilization of electrokinetic phenomena to produce hydrogen gas and to generate electrical power. More particularly, the invention relates both a method and apparatus for the generation of hydrogen gases by flowing a liquid such as water through one or more metal orifices under hydrostatic pressure to thereby form charged liquid microjets, which jets upon collision with a target acting as a source of electrons results in the production of hydrogen gas. Also, via the microjet formation process, a streaming current is produced which may be converted into useable electric power.
2. Description of the Related Art
The renewability, high energy conversion efficiency and non-polluting chemistry of hydrogen-based energy sources have long been known. However, a principal obstacle to implementing a widespread so-called hydrogen economy has been the high costs required for hydrogen production. There are many known methods for producing hydrogen. These methods can be classified into technologies such as biological, chemical, electrochemical and thermal. Each of these known methods is commercially restricted by cost, production rate limitations, or a combination of both.
Currently, commercial supplies of hydrogen are provided by steam reformation of natural gas or coal gasification. These are both thermal processes and are the cheapest methods available. However, these processes consume fossil fuel, and the quantities of hydrogen produced using these processes are not sufficient to initiate and sustain a widespread hydrogen economy. Electrochemical production of hydrogen is another known alternative that is quite advanced, but is a very expensive process.
The combination of declining petroleum reserves and increasing release of carbon, especially carbon dioxide, into the atmosphere necessitates serious efforts to develop renewable and non-polluting chemistry energy economies such as a hydrogen economy. However, there must be cost effective processes available and developed to produce sufficient quantities of hydrogen gas that is needed.
A substantial potential source of hydrogen is water, since it is widely available and an inexpensive commodity. Each water molecule is made of two hydrogen atoms and one oxygen atom. The challenge is that of efficiently separating the hydrogen atoms from the oxygen atoms at low cost and collecting the hydrogen atoms, or molecules formed from them.
Electrokinetic effects refer to electrical effects caused by the relative motion between a liquid, such as water, and a surface. It is well known that electrokinetic charge separation can be effected in a flowing liquid where some of the constituents of the liquid dissociate, forming positive and negative ions. Several researchers have recently explored this phenomenon as a vehicle for electric power development.
For example, in Canadian Patent 24367304, Apparatus and Method for Producing Electrical Energy from Fluid Energy, Kostiuk, et al describe a device which includes one or more electrically non-conductive fluid channels made, for example, from glass. Electrically conductive terminals closely positioned at each end of the channels so as to be in direct communication when fluid is within the channel(s) are electrically connected one to the other. When a fluid such as water is passed through the channel, electrical energy is produced. Noted as a product of the process was the ancillary formation of oxygen gas at one of the terminals and hydrogen gas at the other. Though suggesting one could recover H2 or O2 as desired, nothing is mentioned in the patent concerning the gas generating efficiency of the disclosed process. Additionally, in a related article, the principal researchers reported power generation efficiencies of less than 1% (Electrokinetic Power Generation by Means of Streaming Potentials: a Mobile-Ion-Drain Method to Increase the Streaming Potentials, J. Yang, F. Lu, L. W. Kostiuk and D. Y. Kwok, Journal of Nanoscience and Nanotechnology” Vol. 5, 648-652, 2005).
Heyden and Dekker et al. also explored this phenomenon as reported in Streaming Currents in a Single Nanofluidic Channel, Heyden, and Dekker, Physical Review Letters, PRL 95, 116104 (2005). Therein, the generation of electric current by flowing a pressure driven salt solution (such as KCl) through a rectangular silica nano-channel was described. In later articles Electrokinetic Energy Conversion Efficiency in Nanofluidic Channels, Heyden, Stein, and Dekker, Nano Letters, 2006, Vol. 6, No. 10, 2232-2237, and Power Generation by Pressure-Driven Transport of Ions in Nanofluidic Channels, Heyden, Stein, Meyer and Dekker, Nano Letters 2007, Vol. 7, No. 4, 1022-1025, efficiencies with a single, rectangular nanofluidic channel of up to 12% were estimated, but only about 3.2% realized using different salt solutions. In none of the Dekker articles is the generation of hydrogen gas reported.
What thus still remains is the need for an efficient electrokinetic apparatus and method for co-generating hydrogen gas, while at the same time generating larger streaming currents which may be converted into useful electrical energy.